Carbon-Ceramic Brake Disk Connection Strength and Heat Dissipation
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Solution Overview
Problem
The existing method for manufacturing carbon-ceramic brake disks has issues with filling long fibers into narrow through holes, resulting in low density and weak connection portions, which affects the strength and heat transfer efficiency, leading to inefficient dissipation of frictional heat.
Innovation Solution
The method involves forming a carbon-ceramic brake disk with short fibers in the connection portions between disk portions, allowing for a higher density fill and improved strength, using a core with through holes filled with a mixture of short fibers and phenol resin, and subsequent pyrolysis and silicon infiltration to create a strong, efficient heat transfer structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If long fibers are used in the connection portions, then the heat transfer efficiency is improved, but the filling density decreases and manufacturing difficulty increases
Solution Approach 1:
The patent applies different fiber types to different locations: long fibers are used in the disk portions where heat transfer efficiency is critical, while short fibers are used in the connection portions where filling density and manufacturing ease are more important. This local differentiation resolves the contradiction by optimizing each region for its specific functional requirements.
Solution Approach 2:
The brake disk is segmented into different regions (disk portions and connection portions) with different fiber reinforcement strategies. The connection portions use short fibers for easy filling and high density, while the disk portions use long fibers for heat transfer, allowing each segment to be optimized independently for its specific function.
2Strength
If long fibers are used in the connection portions, then the structural strength is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent differentiates fiber selection by location: short fibers in connection portions for manufacturing simplicity and long fibers in disk portions for strength and heat transfer. This local quality approach maintains structural strength where needed while simplifying manufacturing in connection portions.
Solution Approach 2:
Instead of using long fibers throughout the entire brake disk (which would improve strength but complicate manufacturing), the patent inverts the approach by using short fibers in the connection portions where manufacturing ease is prioritized, and reserves long fibers for the disk portions where their length provides functional benefits.
3Temperature
If the through holes are made narrow to improve cooling efficiency, then the heat dissipation is improved, but the fiber filling becomes difficult
Solution Approach 1:
The patent applies short fibers specifically in the connection portions that fill the through holes, making the filling process easy even when the holes are narrow. The short fibers can navigate narrow spaces more easily than long fibers, thus maintaining manufacturing ease while allowing for narrow cooling channels.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the structural strength and heat transfer efficiency of the connection portions, effectively dissipating frictional heat and preventing thermal distortion, while allowing for easier filling and higher density within complex shapes.
Implementation Method 1
The molded body is inserted inside a furnace and then is pyrolysed under a high temperature to form a preform.
Implementation Method 2
A step infiltrating the preform with a molten silicon is proceeded. Since melting temperature of the silicon is within a range of 1400°C to 2000°C, under the melting temperature, the silicon melts and then is infiltrated into the preform.
Implementation Method 3
During infiltrating the preform with the molten silicon, the silicon combines the preform, which is a carbon, to form a silicon carbide
Implementation Method 4
During which process, the core C in the molded body melts and the core C is removed from the molded body.
Implementation Method 5
When the carbon-ceramic brake disk rotates, air inflows into the through holes of the two disk portions 21, 22 and passes the cooling channels 24 and outflows toward the outer circumference side of the two disk portions 21, 22. Friction heat is dissipated outside while the air passes the cooling channels 24.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present invention comprises a first disk portion, a second disk portion positioned at a predetermined distance from the first disk portion, a plurality of connection portions connecting the first disk portion and the second disk portion, a plurality of cooling channels formed between the connection portions, wherein each of the first disk portion and the second disk portion includes long fibers, and wherein the connection portion includes short fibers. Also, the present invention comprises forming a first layer in a mold by filling a mixture including long fibers into the mold, inserting a core which has a plurality of through holes into the mold so as to be positioned on the first layer, filling a mixture including short fibers into the through holes of the core, forming a second layer on the core by filling a mixture including long fibers into the mold, and pressure-heating the first layer, the core, and the second layer in the mold. The present invention improves the strength of the connection portions which connect two disk portions and improves efficiency of the heat transfer of the connection portion. Therefore, the frictional heat generated in braking operating is efficiently radiated outside. As a result, it is possible to prevent the thermal distortion of a hot part and a brake disk.